Tight lead-through inlet frame device



Jan. 13, 1970 N. A. J. BRATTBERG 3,489,440

TIGHT LEAD-THROUGH INLET FRAME DEVICE Original Filed March 9, 1964 FIGJv PRIOR ART FIGS 13 United States Patent 3,489,440 TIGHT LEAD-THROUGHINLET FRAME DEVICE Nils Arthur Johan Brattberg, Karlskrona, Sweden, as-

signor to Aktiebolaget Lyckeaborgs Bruk, Torskors, Sweden, a corporationof Sweden Original application Mar. 9, 1964, Ser. No. 350,313. Dividedand this application Apr. 18, 1966, Ser. No. 543,371 Int. Cl. F16]39/00, /00 U.S. Cl. 285-192 4 Claims ABSTRACT OF THE DISCLOSURE Alead-through inlet frame device is mounted around a plurality ofelectrical lines such as multi-core-cables, insulated wires, etc.secured in a rigid rectangular frame of the device by compressedresilient rubber blocks embracing each line such that the blocks andlines form a tight filling of the frame. The compression of this fillingis obtained, and may be released, in that the frame is divided into atleast two separate parts being mutually connected by screws extending inthe plane of the frame and, thus, at right angles to the electricallines. When tightening the screw, said filling is compressed between twoopposite sides of the frame and the parts of the frame are pressed intomutual abutment so that the compression is limited and well-defined. Theframe and/or the filling has a smooth plane surface area in the form ofa plane rectangular frame, which surface may be sealingly pressedagainst a corresponding surface surrounding an aperture in a wallthrough which said lines pass. The frame is pressed against the wall byscrews passing through or into the wall and frame and extendingperpendicularly to the screws for compressing the filling of the frame.The rubber blocks are rectangular bodies provided with passages for theindividual separate electrical lines and form a modular set to fillentirely said frame. When removing, adding or changing any of the lines,the compression screws are loosened to release the compression,preferably after having removed the device from the wall, and then anyblocks and lines may be individually removed or changed. The deviceseals said wall in an airtight manner even under fairly high pressure.Also flexible and rigid tubes may extend through the device.

This application is a division from my application Ser. No. 350,313filed Mar. 9, 1964 now United States Patent No. 3,282,544.

Lead-through inlet frame devices for electrical lines such as single ormultiple core cables, flexible leads and insulated or even uninsulatedconductors are normally made for one single line only so that the numberof inlet frame devices required is equal to the number of lines to bepassed through. Particularly, if a plurality of lines should be passedclose to one another through a wall, considerable difficulties arise andrender difiicult mounting and demounting of the frame devices and thelines, for example when a line has to be added or replaced. Suchdifficulties may be avoided to a large extent by inlet frame devices ofthe type shown in FIGS. 1 and 2 disclosing prior art, see for instanceUS, Patent No. 2,732,226.

The known inlet frame device shown in FIGS. 1 and 2 forms prior art andcomprises a metal frame 1, two clamping pressure plates 11 therein whichare movable in one and the same direction in the plane of the frame ofthe device, resilient clamping blocks 3 and resilient filling plates 12.For each individual line, a pair of blocks 3 is provided, every blockhaving a semi-circular (semicylindrical) recess adapted to the diameterof the line to be clamped. One pair of such blocks 3 normally has a3,489,440 Patented Jan. 13, 1970 square cross-section or contour.Similar square or semisquare resilient blocks having no recess may beused as filling blocks within the area between the pressure plates 11.The sides of all blocks 3 and 11 to be inserted into the inlet framedevice may be dimensioned in accordance with a modular system as may beseen by way of example from FIG. 1. The inlet frame device may be madetight and the lines may be clamped between the associated blocks 3 bymoving the two pressure plates 11 towards one another by means of anadjustable screw clamp or similar means. By this procedure, spaces occurbetween the plates 11 and the adjacent sides of the frame 1 so that suchspaces have to be filled with the resilient filling plates 12. Then, thepressure plates 11 are released so that a pressure equilibrium isobtained, and the pressure to which the blocks 3 and plates 12 aresubjected in the direction of the centre line XX will have anapproximately uniform distribution so that all of said resilientelements are subjected to approximately one and the same unit pressureset up by their own resilience.

It is also known to use one pressure plate 11 only and to press thisplate towards the blocks 3 by means of a screw which is approximatelyco-axial with the axis XX and extends through a thread hole in one shortside of the frame and engages the pressure plate. The spacing betweenthe pressure plate and the associated short side of the frame has to bemade tight by being filled with filling plates or bodies which, however,have to be pressed by separate special clamps or the like into tightcontact with the walls of the spacing. I

The above known contsructions as well as other similar constructionshave disadvantages which are fairly troublesome in practice. A few onlymay be mentioned. In most cases practical difficulties arise withrespect to the application of tools irrespective of whether a clamp isused for the system shown in FIGS. 1 and 2 or a screw spanner is usedfor a pressure screw extending in the direction of axis XX. It should benoted that such clamping has to be carried out when the lines 4 extendthrough the inlet, and that the lines may be highly rigid and thick, Thesize and position of the area occupied by the resilient blocks and thelines is not predetermined and depends on the distance through which thepressure plate or plates 11 have been moved during the process ofclamping. If the whole of the inlet has to form a constructive unit tobe mounted upon a wall, it may be difficult to ensure a fully tightcircumferential contact and a satisfying contact pressure engagementeverywhere around the rectangular lead-through aperture of the wall,more particularly in view of the indefinite final position of thepressure plate. Such and other disadvantages are still more cumbersomeif, later on, one of the lines 4 has to be replaced, for example becauseit has been damaged or because a line of greater or smallercross-sectional area has to be used. In limited spaces such as inaircraft and ships, air or pressure tight apparatus boxes, switchboards, distribution boxes, enclosed switchgears etc. Where a greatnumber of lines being relatively rigidly lain and fixed pass through thelead-through inlet, said problems will prove difficult.

It is an object of the invention to eliminate a number of saiddisadvantages and to realise a compact resistant construction.

More specifically the general object of the invention is attained by animproved and more simplified construction for the lead-through by meansof which it has been possible to eliminate the clamping pressure platesand the resilient filling plates required for the prior construction.

The improved construction for the lead-through comprises a rectangularframe divided perpendicularly into at least two parts and screws whichextend through one of the parts and are threaded into and terminate inthe other part. The aperture within the frame is filled, and at leastapart of this filling consists of a modular set of rectangular-sectionparallelepipeda'l: blocks, four of whose plane faces are parallel to thefour sides of the frame, these blocks being at least partially resilientand a plurality of which are divided centrally intermediate two of theplane parallel faces with mutually complementary semi-cylindricalrecesses in the juxtaposed surfaces of each of the divided blocks forthrough-passage of an electrical line. The screws serve to press theframe parts into mutual abutment whereby the filling is compressedbetween two opposite parallel sides of the frame, the compression beinglimited by the abutment. The overall structure is provided with asubstantially smooth plane surface and means for pressing it onto thewall in a sealing manner such that the surface surrounds all of theelectrical lines passing through it and through the wall.

The foregoing as well as other objects and advantages inherent in theimproved construction for the lead-through will become more apparentfrom the following detailed description of several embodiments thereofand from the accompanying drawings wherein:

FIGS. 1 and 2 show the known inlet frame device as seen in the directionof the lines and transversely thereto, respectively.

FIGS. 3 and 4 show an inlet frame device according to the invention asseen in the direction of the lines and transversely thereto,respectively.

FIGS. 5 and 6 show another inlet frame device in accordance with theinvention in the same manner as in FIGS. 3 and 4.

FIGS. 7 and 8 show a third inlet frame device in accordance with theinvention in the same manner as in FIGS. 3 and 4.

With reference now to the drawings, FIG. 3 is a view of a lead-throughinlet frame device seen in the direction of the conductor lines 4extending through the inlet frame device, and FIG. 4 is a side view ofthis inlet frame device which comprises a frame composed of a U-shapedportion 1a and a yoke 1b which can be fixed to the two free ends ofpart'la by means of two preferably hexagonal screws 13. The space orarea enclosed by said frame forms the lead-through aperture or window ofthe frame device and is filled with resilient, rectangularparallelepipedic clamping blocks 3a, 3b, 3c of various sizes. The blocksare preferably made of synthetic rubber but may alternatively consist ofresilient plastic material, natural rubber or another suitable material.The clamping blocks are arranged in pairs such that the four outer sidesof each pair of blocks, such as 3c, forms a square and that eachindividual block has a semi-square form, that is, the crosssectionalside ratio of each single block is 2:1. Each of the two blocks of a pairhas a semi-cylindrical recess (semi-circular in cross-section) such thatthe two recesses of the pair face one another and embrace an electricalline, such as a cable, having a diameter substantially equal to that ofthe tWo associated recesses embracing the conductor line. The sides ofthe blocks are dimensioned in accordance with a suitable modular systemso that blocks adapted to conductor lines of different diameters can bejoined such that the set of blocks to be provided in the above mentionedaperture of the frame forms a rectangle which approximately correspondsto the rectangular aperture but is larger than the aperture when theblocks are not compressed. Furthermore, semi-square or, preferably,square resilient blocks which have no recesses may be used to fill anyempty areas of said rectangle which will not be used to containelectrical lines. For this object it is also possible to use rectangularfilling blocks having a side ratio exceeding 2:1 but, nevertheless, inaccordance with the modular system of the other blocks.

In the inlet frame device in FIGS. 3 and 4 the set of blocks comprisesclamping blocks 3a, 3b, 3c of different sizes for conductor lines ofdifferent diameters, respectively, the non-compressed relaxed set ofblocks covering an area slightly exceeding that of the frame aperturesuch that the set of blocks shown in the non-compressed state projectsbeyond the free ends of the U-shaped fra me part 1a. In a directionparallel to the yoke 1b and of the bottom portion of the U-shaped part1a, the width of the block set should not, however, considerably exceedthe width of the frame aperture to avoid the necessity of forcing theblocks into the space between the legs of part 1a under appreciablecompression of the blocks 3. The thickest cable is embraced by the pairof bl0Cks 3c, and the finest cables or leads are embraced each by a pairof blocks 3a. After having inserted the blocks and the lines thereininto the frame 1a, 1b the compression screws 13 are tightened to pressthe yoke 1b towards and against the free ends of the two legs of theframe part 1a until the yoke is tightly abutting said ends or a gasketinserted between the yoke and said ends. Now, the inlet as a whole formsa constructional unit which is freely movable together with the linespassing therethrough and may be attached into or upon a wall which isprovided with a lead-through aperture of similar size and form as theframe aperture limited by the frame parts la and 1b, In this compressedstate, the inlet is impermeable to liquids and gases such as water andair which cannot pass through the inlet frame device in the direction ofthe electrical lines. Such inlet may readily be dimensioned such that itremains impervious even if the difference of the pressures on eitherside of the frame is considerable and say, of the order of many tens oflbs. (many atmospheres). Furthermore, it is not diflicult to seal thejoints existing between the inlet frame device and said wall so thatliquid, or gas, cannot penetrate said joints, that is, cannot passaround the periphery of the frame to the other side of it.

The frame 10, lb or, if necessary, flanges, projections or eyelets etc.extending from the frame, may be provided with holes or bores 14extending in the leadthrough direction (direction of the electricallines) so that the frame may be pressed and fixed to a wall 15 by screws16 passing through the holes 14, the wall .15 and screws 16 beingomitted in FIG. 3. As the final position of the yoke 1b, that is theposition of the yoke when screwed tightly to the ends of the legs ofpart 1a, is definitely predetermined and unvariable, it is a simplemeasure to use a rectangular, frame-shaped plane packing or gasket ofrubber or of any well-known sealing material between the frame la, 1b ofthe inlet frame device and the wall. The inner and outer peripheries ofsuch seal may approximately coincide with those of the frame 1a, 1b.Sealing of the frame against or within a wall may be carried out inanother manner. Thus, the block set itself may be used as a sealingmeans if all blocks at least slightly extend beyond the frame in thelead-through direction thereof with co-planar end surfaces of the blocksand if the aperture of the wall is slightly smaller than that of theframe. In such a case the four edge zones of the periphery of the blockset may be pressed directly, for example by screws, against the edgezones of the aperture of the wall, and it is possible to use the .samescrews 13 for such sealing as for attaching the leadthrough inlet framedevice to the wall.

The two legs of the frame part 1a, and if desired also the yoke or thebottom portion of this part, may be provided with set means such asguiding recesses for the elastic blocks so that two or three or all ofthe four edges (or pairs of edges) of the set of blocks are located insuch recesses. Normally it is simpler and better, however, to useprojecting flanges instead of guide recesses, for example such that theset of blocks as a whole cannot be displaced in the frame in thedirection away from the wall but, if the set is not compressed, can bedisplaced towards the wall.

FIGS. 5 and 6 show a similar inlet frame device as FIGS. 3 and 4,respectively, with the exception that the frame is constituted by twoparallel yokes 1b and 1c and two spaced separate legs 1a. The legs maybe rigidly interconnected. One of the yokes, e.g. 1c, may be unvariablyfixed to the 'legs 1a by screws so that the inlet frame device can beused in the same way as that described above and shown in FIGS. 3 and 4.If the set of blocks in its decompressed state extends in the directionof the legsla considerably beyond the ends of the legs, there is thedanger that those blocks which are not guided by the legs will tend toexpand laterally, when the set is compressed by the yoke 11) so that thelateral sides of the blocks will be clamped between the yoke 11) and thefree ends of the legs 41a because the spacing or gap between yoke 1b andsaid ends is too large. In such case, both of the yokes 1b and '10 maybe released from the legs so that the width of the gap between each yokeand the associated leg end is halved. The use of two yokes has also theadvantage that it is not necessary to produce a U-shaped frame part andthat the length (height) of the set of blocks in the direction betweenthe yokes may be chosen much greater than if one movable yoke is used.

It is possible to select types of plastic or rubber material such ascertain neoprene rubber types, which during compression do notappreciably expand in a direction perpendicular to the direction ofpressure.

Besides as may be seen from FIG. 5 lead-through areas may exist whichare not required at all or which are provided as spare areas and,therefore, are filled with preferably square elastic blocks 3d notembracing an electrical line. All remaining elements of the inlet framedevice shown in FIG. 5 may be similar to the corresponding elements inFIGS. 3 and 4 and may serve the same purpose.

FIGS. 7 and 8 show a further lead-through inlet frame device differingfrom those described above substantially in that the frame isconstituted by two U-shaped parts 111, 1b the free ends of which opposeone another and may be pressed against one another by pressure screws13. The frame parts are shown without other guides and set means thanthe screws 13. It is possible, of course, to provide guides of any typesuch as set pins, engaging longitudinal portions of the frame parts etc.ensuring that these two parts always remain aligned during and aftercompression of the set of blocks surrounded by the frame.

What I claim is:

1. A device for mounting around a plurality of electrical lines tosupport said lines in a passthrough opening in a wall which comprises anassembly of a frame having a rectangular opening, said frame beingdivided perpendicularly to the plane of the frame into at least twoparts connected together in abutting relation by screw means extendingthrough at least one of said frame parts and being threaded into andterminating within another of said frame parts, and a modular set ofrectangular-section parallelepipedal filler blocks made from a resilientmaterial filling said frame opening, four of the plane faces of saidfiller blocks being parallel to the four sides of the frame forming theopening therein, at least some of said blocks being divided centrallyintermediate two of said plane parallel faces with mutuallycomplementary semi-cylindrical recesses in the juxtaposed surfaces ofeach of said divided blocks for through passage of an electrical line,the sum of the areas of said resilient filler blocks when in anuncompressed state prior to tightening of said screw means to draw saidframe parts together in abutting relation exceeding the area of thefinal frame opening whereby said filler blocks become compressed againsteach other and against all four sides of the frame opening as saidscrews are tightened, said assembly of frame and filler blocks beingprovided with a substantially smooth plane surface so as to establish asealing contact with the surface of the wall surrounding said openingtherein, and said parts constituting said frame being provided withopenings extending therethrough perpendicular to the plane of said framefor receiving means by which said assembly is fastened in place at saidwall opening.

2. The device as defined in claim 1 wherein said frame is constituted bytwo parts connected together by said screws, one of said parts having aU-shaped configuration which forms three of the four sides of saidrectangular frame opening and the other part being in the form of an endyoke which forms the remaining side of said frame opening, said end yokebeing provided with unthreaded holes through which said screws pass andthe end faces of the legs of said U-shaped part being provided withthreaded bores for receiving said screws.

3. The device as defined in claim 1 wherein said frame is constituted bya pair of parallel spaced side members and a pair of end yokes, said endyokes being provided with unthreaded holes through which said screwspass and the end faces at the opposite ends of said side members beingprovided with threaded bores for receiving said screws.

4. The device as defined in claim 1 wherein said frame is constituted bya pair of U-shaped frame members which are arranged with their openingsin confronting relation, and said screws extend through unthreaded boresin one of said U-shaped frame members into threaded bores in the other:U-shaped frame member.

References Cited UNITED STATES PATENTS 2,732,226 1/1956 Brattberg 285l922,951,565 9/1960 Haglund 287189.36

FOREIGN PATENTS 501,185 11/1954 Italy.

DAVID J. WILLTAMOWSKY, Primary Examiner WAYNE L. SHEDDA, AssistantExaminer U.,S. c1. X.R. 2 8-56

